WINTER STORM WATCH ISSUED DUE TO INCREASING THREAT OF ICE
Winter weather possible Tuesday night into Wednesday morning for portions of the Piedmont, foothills, and western NC. I talked about this a little yesterday now it is coming better together.
WHAT: During the day on Tuesday, we will be mostly dry with some sunshine, by afternoon clouds will start to move in. By later Tuesday evening wintery precipitation will start to impact the western areas, the timing of the arrival of the precipitation is critical for amounts and impacts. This is a favorable pattern for a winter storm for our state; however, it appears the significant precipitation will arrive Tuesday night and Wednesday, after the warming aloft will be well underway. As the precipitation becomes more widespread in the western and northern Piedmont into the foothills and mountains by nightfall or during the evening, the temperatures are expected to fall to around or slightly below 32 in much of the areas. A light accumulation of ice may cause treacherous road conditions Tuesday overnight into Wednesday morning. The best chance of freezing rain will be from i85 west, see the map below. Clouds will move in Tuesday evening, before light freezing rain and freezing drizzle starts from the Triangle west. A light wintery mix of sleet might start after midnight before changing to all freezing rain or freezing drizzle. The freezing rain will remain around until 10-11am when temperatures climb above freezing.
Freezing rain is expected from a winter storm Tuesday night into Wednesday, above is the forecast map.
PINK: 0.05-0.10 of ice: This area will see a light glaze of ice from the Triangle west a Winter Weather Advisory may be issued later today
LIGHT BLUE- 0.10-0.25 of ice: This area will see a moderate ice event with build up on trees and power lines possible
Important to know ground temperatures and the tilt of the sun are all working against seeing significant icing.
IMPACTS: Hazardous travel on bridges and overpasses or any elevated surfaces, ground temperatures are above freezing some main treated roads should be fine.
A Winter Storm Watch has been issued for Avery-Yancey-Mitchell-Caldwell Mountains-Burke Mountains- McDowell Mountains- Ashe-Alleghany NC-Surry-Watauga-Wilkes. More watches and Advisories will be issued later today.
Bottom Line: The amount and depth of cold air along with the timing of the precipitation remain uncertain. This will be a CAD (Cold air Damming) event, models do a bad job forecasting these events. Thus, I have taken years of knowledge of forecasting these types of events to create the ice maps (will watch trends on models today). I do expect a period of sleet, changing to freezing rain across a portion from just west of Raleigh to the mountains. Impacts should be limited at this point, however be prepared for some impacts Wednesday morning especially areas that see higher icing . As always stay tuned for more updates on our Facebook page and website. If you have questions message the Facebook page, as the website message will not work. Another full update will be posted later this evening.